Though not technically a window manager, wmutils is a suite of command-line tools that give you everything you need to manipulate and arrange X windows through scripts and hotkeys.
Ranked in these QuestionsQuestion Ranking
Pro Follows the Unix philosophy
In classic UNIX fashion, each tool within wmutils does one thing and aims to do it well.
Con Requires heavy scripting
Almost no behavior is defined out-of-the-box. All interaction must be scripted through hotkeys and mouse bindings.